Method decode

framework/scene_graph/components/image/astc.cpp:153–209

}

void Astc::decode(BlockDim blockdim, VkExtent3D extent, const uint8_t *compressed_data, uint32_t compressed_size)
{
	PROFILE_SCOPE("Decode ASTC Image");

	// Actual decoding
	astcenc_swizzle swizzle = {ASTCENC_SWZ_R, ASTCENC_SWZ_G, ASTCENC_SWZ_B, ASTCENC_SWZ_A};
	// Configure the compressor run
	astcenc_config astc_config;
	auto           atscresult = astcenc_config_init(
        ASTCENC_PRF_LDR_SRGB,
        blockdim.x,
        blockdim.y,
        blockdim.z,
        ASTCENC_PRE_FAST,
        ASTCENC_FLG_DECOMPRESS_ONLY,
        &astc_config);

	if (atscresult != ASTCENC_SUCCESS)
	{
		throw std::runtime_error{"Error initializing astc"};
	}

	if (extent.width == 0 || extent.height == 0 || extent.depth == 0)
	{
		throw std::runtime_error{"Error reading astc: invalid size"};
	}

	// Allocate working state given config and thread_count
	astcenc_context *astc_context;
	astcenc_context_alloc(&astc_config, 1, &astc_context);

	astcenc_image decoded{};
	decoded.dim_x     = extent.width;
	decoded.dim_y     = extent.height;
	decoded.dim_z     = extent.depth;
	decoded.data_type = ASTCENC_TYPE_U8;

	// allocate storage for the decoded image
	// The astcenc_decompress_image function will write directly to the image data vector
	auto  uncompressed_size = decoded.dim_x * decoded.dim_y * decoded.dim_z * 4;
	auto &decoded_data      = get_mut_data();
	decoded_data.resize(uncompressed_size);
	void *data_ptr = static_cast<void *>(decoded_data.data());
	decoded.data   = &data_ptr;

	atscresult = astcenc_decompress_image(astc_context, compressed_data, compressed_size, &decoded, &swizzle, 0);
	if (atscresult != ASTCENC_SUCCESS)
	{
		throw std::runtime_error("Error decoding astc");
	}
	astcenc_context_free(astc_context);

	set_format(VK_FORMAT_R8G8B8A8_SRGB);
	set_width(decoded.dim_x);
	set_height(decoded.dim_y);
	set_depth(decoded.dim_z);
}